Jin-Chang Guo

Transition metal-boron complexes BnM: from bowls (n = 8-14) to tires (n = 14).

Transition metal–boron complexes BnM have been predicted at density functional theory level to be molecular bowls (n = 8–14) hosting a transition metal atom (M) inside or molecular tires (n = 14) centered with a transition metal atom. Small Bn clusters prove to be effective inorganic ligands to all the VB–VIIIB transition metal elements in the periodic table. Density functional evidences obtained in this work strongly suggest that bowl‐shaped fullerene analogues of Bn units exist in small BnM complexes and the bowl‐to‐tire structural transition occur to the first‐row transition metal complexes BnM (M = Mn, Fe, Co) at n = 14, a size obviously smaller than n = 20 where the 2D‐3D structural transition occurs to bare Bn. The half‐sandwich‐type B12Cr (C3v), full sandwich‐type (B12)2Cr (D3d), bowl‐shaped B14Fe (C2), and tire‐shaped B14Fe (D7d) and B14Fe− (C7v) are the most interesting prototypes to be targeted in future experiments. These BnM complexes may serve as building blocks to form extended boron‐rich BnMm tubes or cages (m ≥ 2) or as structural units to be placed inside carbon nanotubes with suitable diameters.

Carbon boronyls: Species with higher viable possibility than boron carbonyls at the density functional theory

Density functional theory investigations indicate that carbon boronyls (CBO)n (n = 3–7) are considerably more stable in thermodynamics than their boron carbonyl isomers (BCO)n and exhibit aromaticity throughout the whole series. The extra stabilities of (CBO)n originate from their frontier π molecular orbitals delocalized over the Dnh Cn central rings which are absent in (BCO)n. It is expected that experimental characterization of these (CBO)n species may open a new branch of chemistry on carbon boronyls.